Final answer:
The required fixture above a urinal with a flushometer is a trap, which holds water to prevent sewer gases from entering the bathroom environment, ensuring health and safety standards.
Step-by-step explanation:
The question you've asked pertains to fixtures required above the highest part of a urinal equipped with a flushometer.
In a usual setting such as a bathroom or restroom, while ventilation may be important for the removal of odors, and lighting is generally necessary for visibility, and mirrors are often installed for personal grooming, it is the trap that is required as part of the plumbing system.
A trap is a device that holds water to prevent sewer gases from entering the bathroom environment, which is fundamental to maintaining health and safety standards.
The other options, while common in many bathrooms, are not required by plumbing standards or building codes. Hence, the answer is D. A trap is required.
In a urinal equipped with a flushometer, it is not necessary to have a mirror above the highest part. Ventilation is required in restrooms to remove odors and maintain air quality.
A light fixture can be installed for better visibility, especially in dimly lit restrooms. However, in this scenario, the question does not specify the need for a light fixture. The most important component that is required above the highest part of a urinal equipped with a flushometer is a trap.
A trap is a plumbing device that prevents foul odors and gases from entering the restroom through the plumbing system. It ensures proper drainage and prevents the backflow of waste.